History of bronchitis. Gets wheeze, often get cold and cough. Had an allergic episode. Treated with cetrizine. Decrease in AEC count. Advice?

hi,
My son is 10 years old, he has history of bronchitis. He gets wheeze which is often preceeded by cold and fever (indicating an infection). He recently had an allergic episode which lasted for 15 days. Initially he was treated with cetrizine for about a week . I got an AEC test done since he got 1 or 2 rashes despite treatment, this revealed a value of 1200. I continued treatment with CPM. After a week, i got him retested for AEC which revealed a value of 900 indicating decrease in AEC count. Please advise me